1366 - Incorrect integer value: '' for column `CP_as15`.`whos_online`.`customer_id` at row 1

insert into whos_online (customer_id, full_name, session_id, ip_address, time_entry, time_last_click, last_page_url) values ('', 'Guest', '9n2k2e4rp7p89gulg2nced2ci4', '3.147.64.131', '1739000710', '1739000710', '/index.php?XTCsid=phknodh461cpg07ie5v3k6t3b7&cat=c990_W--rth-Werkzeug-Akku.html')

[XT SQL Error]